[PATCH] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[PATCH] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[Hans de Goede]

Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
handle Command Complete") was (presumably) meant to only refactor things
without any functional changes.

But it does have one undesirable side-effect, before *status would always
be set to skb->data[0] and it might be overridden by some of the opcode
specific handling. While now it always set by the opcode specific handlers.
This means that if the opcode is not known *status does not get set any
more at all!

This behavior change has broken bluetooth support for BCM4343A0 HCIs,
the hci_bcm.c code tries to configure UART attached HCIs at a higher
baudraute using vendor specific opcodes. The BCM4343A0 does not
support this and this used to simply fail:

[   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
[   25.646481] Bluetooth: hci0: Failed to set baudrate

After which things would continue with the initial baudraute. But now
that hci_cmd_complete_evt() no longer sets status for unknown opcodes
*status is left at 0. This causes the hci_bcm.c code to think the baudraute
has been changed on the HCI side and to also adjust the UART baudrate,
after which communication with the HCI is broken, leading to:

[   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
[   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)

And non working bluetooth. Fix this by restoring the previous
default "*status = skb->data[0]" handling for unknown opcodes.

Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 net/bluetooth/hci_event.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index af17dfb20e01..fda31d558ded 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3996,6 +3996,13 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
 			break;
 		}
 	}
+	if (i == ARRAY_SIZE(hci_cc_table)) {
+		/* Unknown opcode, assume byte 0 contains the status, so
+		 * that e.g. __hci_cmd_sync() properly returns errors
+		 * for vendor specific commands send by HCI drivers.
+		 */
+		*status = skb->data[0];
+	}
 
 	handle_cmd_cnt_and_timer(hdev, ev->ncmd);
 
-- 
2.37.1

RE: Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2070 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=665926

---Test result---

Test Summary:
CheckPatch                    FAIL      1.88 seconds
GitLint                       PASS      1.09 seconds
SubjectPrefix                 PASS      0.84 seconds
BuildKernel                   PASS      33.71 seconds
BuildKernel32                 PASS      29.15 seconds
Incremental Build with patchesPASS      40.88 seconds
TestRunner: Setup             PASS      486.89 seconds
TestRunner: l2cap-tester      PASS      17.54 seconds
TestRunner: bnep-tester       PASS      6.73 seconds
TestRunner: mgmt-tester       PASS      104.38 seconds
TestRunner: rfcomm-tester     PASS      10.12 seconds
TestRunner: sco-tester        PASS      9.90 seconds
TestRunner: smp-tester        PASS      9.92 seconds
TestRunner: userchan-tester   PASS      7.00 seconds

Details
##############################
Test: CheckPatch - FAIL - 1.88 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
Bluetooth: hci_event: Fix vendor (unknown) opcode status handling\ERROR:GIT_COMMIT_ID: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'Commit fatal: unsaf ("ace/src' is owned by someone else)")'
#68: 
Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
handle Command Complete") was (presumably) meant to only refactor things

total: 1 errors, 0 warnings, 0 checks, 13 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

/github/workspace/src/12938271.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.




---
Regards,
Linux Bluetooth

Re: Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[Hans de Goede]

Hi,

On 8/7/22 23:59, bluez.test.bot@gmail.com wrote:
> This is automated email and please do not reply to this email!
> 
> Dear submitter,
> 
> Thank you for submitting the patches to the linux bluetooth mailing list.
> This is a CI test results with your patch series:
> PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=665926
> 
> ---Test result---
> 
> Test Summary:
> CheckPatch                    FAIL      1.88 seconds
> GitLint                       PASS      1.09 seconds
> SubjectPrefix                 PASS      0.84 seconds
> BuildKernel                   PASS      33.71 seconds
> BuildKernel32                 PASS      29.15 seconds
> Incremental Build with patchesPASS      40.88 seconds
> TestRunner: Setup             PASS      486.89 seconds
> TestRunner: l2cap-tester      PASS      17.54 seconds
> TestRunner: bnep-tester       PASS      6.73 seconds
> TestRunner: mgmt-tester       PASS      104.38 seconds
> TestRunner: rfcomm-tester     PASS      10.12 seconds
> TestRunner: sco-tester        PASS      9.90 seconds
> TestRunner: smp-tester        PASS      9.92 seconds
> TestRunner: userchan-tester   PASS      7.00 seconds
> 
> Details
> ##############################
> Test: CheckPatch - FAIL - 1.88 seconds
> Run checkpatch.pl script with rule in .checkpatch.conf
> Bluetooth: hci_event: Fix vendor (unknown) opcode status handling\ERROR:GIT_COMMIT_ID: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'Commit fatal: unsaf ("ace/src' is owned by someone else)")'
> #68: 
> Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
> handle Command Complete") was (presumably) meant to only refactor things
> 
> total: 1 errors, 0 warnings, 0 checks, 13 lines checked

Note no idea why the bluez.test.bot infra is emitting this
warning. The git commit id style is correct and locally
checkpatch does not generate this warning.

Regards,

Hans

Re: [PATCH] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[Luiz Augusto von Dentz]

Hi Hans,

On Sun, Aug 7, 2022 at 1:57 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
> handle Command Complete") was (presumably) meant to only refactor things
> without any functional changes.
>
> But it does have one undesirable side-effect, before *status would always
> be set to skb->data[0] and it might be overridden by some of the opcode
> specific handling. While now it always set by the opcode specific handlers.
> This means that if the opcode is not known *status does not get set any
> more at all!
>
> This behavior change has broken bluetooth support for BCM4343A0 HCIs,
> the hci_bcm.c code tries to configure UART attached HCIs at a higher
> baudraute using vendor specific opcodes. The BCM4343A0 does not
> support this and this used to simply fail:
>
> [   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
> [   25.646481] Bluetooth: hci0: Failed to set baudrate
>
> After which things would continue with the initial baudraute. But now
> that hci_cmd_complete_evt() no longer sets status for unknown opcodes
> *status is left at 0. This causes the hci_bcm.c code to think the baudraute
> has been changed on the HCI side and to also adjust the UART baudrate,
> after which communication with the HCI is broken, leading to:
>
> [   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
> [   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)
>
> And non working bluetooth. Fix this by restoring the previous
> default "*status = skb->data[0]" handling for unknown opcodes.
>
> Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
> Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  net/bluetooth/hci_event.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index af17dfb20e01..fda31d558ded 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -3996,6 +3996,13 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
>                         break;
>                 }
>         }
> +       if (i == ARRAY_SIZE(hci_cc_table)) {
> +               /* Unknown opcode, assume byte 0 contains the status, so
> +                * that e.g. __hci_cmd_sync() properly returns errors
> +                * for vendor specific commands send by HCI drivers.
> +                */
> +               *status = skb->data[0];
> +       }

The format of return parameters in command is not defined by the spec:

BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E
page 2189:

Return_Parameters:
Size: Depends on command

This is the return parameter(s) for the command specified in the
Command_Opcode event parameter. See each command’s definition for
the list of return parameters associated with that command.

So assuming the status is the first by is not quite right, although
for the standard ones that seems to be valid, I think the best way to
resolve this would have been to check if it a vendor command and then
have the driver handle it or perhaps have some means for the driver to
register it vendor_cc_table, we can perhaps have this as a workaround
for now and only really change how we parse the cc for vendor commands
if a vendor decide not to have a status as first parameter but Id
probably leave a comment that quoting the spec that reminds us this
code may need changing.

>         handle_cmd_cnt_and_timer(hdev, ev->ncmd);
>
> --
> 2.37.1
>


-- 
Luiz Augusto von Dentz

Re: [PATCH] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[Luiz Augusto von Dentz]

Hi Hans,

On Mon, Aug 8, 2022 at 12:58 PM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Hans,
>
> On Sun, Aug 7, 2022 at 1:57 PM Hans de Goede <hdegoede@redhat.com> wrote:
> >
> > Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
> > handle Command Complete") was (presumably) meant to only refactor things
> > without any functional changes.
> >
> > But it does have one undesirable side-effect, before *status would always
> > be set to skb->data[0] and it might be overridden by some of the opcode
> > specific handling. While now it always set by the opcode specific handlers.
> > This means that if the opcode is not known *status does not get set any
> > more at all!
> >
> > This behavior change has broken bluetooth support for BCM4343A0 HCIs,
> > the hci_bcm.c code tries to configure UART attached HCIs at a higher
> > baudraute using vendor specific opcodes. The BCM4343A0 does not
> > support this and this used to simply fail:
> >
> > [   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
> > [   25.646481] Bluetooth: hci0: Failed to set baudrate
> >
> > After which things would continue with the initial baudraute. But now
> > that hci_cmd_complete_evt() no longer sets status for unknown opcodes
> > *status is left at 0. This causes the hci_bcm.c code to think the baudraute
> > has been changed on the HCI side and to also adjust the UART baudrate,
> > after which communication with the HCI is broken, leading to:
> >
> > [   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
> > [   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)
> >
> > And non working bluetooth. Fix this by restoring the previous
> > default "*status = skb->data[0]" handling for unknown opcodes.
> >
> > Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
> > Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> > Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> > ---
> >  net/bluetooth/hci_event.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> > index af17dfb20e01..fda31d558ded 100644
> > --- a/net/bluetooth/hci_event.c
> > +++ b/net/bluetooth/hci_event.c
> > @@ -3996,6 +3996,13 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
> >                         break;
> >                 }
> >         }
> > +       if (i == ARRAY_SIZE(hci_cc_table)) {
> > +               /* Unknown opcode, assume byte 0 contains the status, so
> > +                * that e.g. __hci_cmd_sync() properly returns errors
> > +                * for vendor specific commands send by HCI drivers.
> > +                */
> > +               *status = skb->data[0];
> > +       }
>
> The format of return parameters in command is not defined by the spec:
>
> BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E
> page 2189:
>
> Return_Parameters:
> Size: Depends on command
>
> This is the return parameter(s) for the command specified in the
> Command_Opcode event parameter. See each command’s definition for
> the list of return parameters associated with that command.
>
> So assuming the status is the first by is not quite right, although
> for the standard ones that seems to be valid, I think the best way to
> resolve this would have been to check if it a vendor command and then
> have the driver handle it or perhaps have some means for the driver to
> register it vendor_cc_table, we can perhaps have this as a workaround
> for now and only really change how we parse the cc for vendor commands
> if a vendor decide not to have a status as first parameter but Id
> probably leave a comment that quoting the spec that reminds us this
> code may need changing.

Are you still planning to send updates for this, I consider this quite
urgent given that it can break support with some vendors.

> >         handle_cmd_cnt_and_timer(hdev, ev->ncmd);
> >
> > --
> > 2.37.1
> >
>
>
> --
> Luiz Augusto von Dentz



-- 
Luiz Augusto von Dentz

Re: [PATCH] Bluetooth: hci_event: Fix vendor (unknown) opcode status handling

[Hans de Goede]

Hi Luiz,

On 8/11/22 00:26, Luiz Augusto von Dentz wrote:
> Hi Hans,
> 
> On Mon, Aug 8, 2022 at 12:58 PM Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
>>
>> Hi Hans,
>>
>> On Sun, Aug 7, 2022 at 1:57 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>>
>>> Commit c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to
>>> handle Command Complete") was (presumably) meant to only refactor things
>>> without any functional changes.
>>>
>>> But it does have one undesirable side-effect, before *status would always
>>> be set to skb->data[0] and it might be overridden by some of the opcode
>>> specific handling. While now it always set by the opcode specific handlers.
>>> This means that if the opcode is not known *status does not get set any
>>> more at all!
>>>
>>> This behavior change has broken bluetooth support for BCM4343A0 HCIs,
>>> the hci_bcm.c code tries to configure UART attached HCIs at a higher
>>> baudraute using vendor specific opcodes. The BCM4343A0 does not
>>> support this and this used to simply fail:
>>>
>>> [   25.646442] Bluetooth: hci0: BCM: failed to write clock (-56)
>>> [   25.646481] Bluetooth: hci0: Failed to set baudrate
>>>
>>> After which things would continue with the initial baudraute. But now
>>> that hci_cmd_complete_evt() no longer sets status for unknown opcodes
>>> *status is left at 0. This causes the hci_bcm.c code to think the baudraute
>>> has been changed on the HCI side and to also adjust the UART baudrate,
>>> after which communication with the HCI is broken, leading to:
>>>
>>> [   28.579042] Bluetooth: hci0: command 0x0c03 tx timeout
>>> [   36.961601] Bluetooth: hci0: BCM: Reset failed (-110)
>>>
>>> And non working bluetooth. Fix this by restoring the previous
>>> default "*status = skb->data[0]" handling for unknown opcodes.
>>>
>>> Fixes: c8992cffbe74 ("Bluetooth: hci_event: Use of a function table to handle Command Complete")
>>> Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>> ---
>>>  net/bluetooth/hci_event.c | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>>
>>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>>> index af17dfb20e01..fda31d558ded 100644
>>> --- a/net/bluetooth/hci_event.c
>>> +++ b/net/bluetooth/hci_event.c
>>> @@ -3996,6 +3996,13 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, void *data,
>>>                         break;
>>>                 }
>>>         }
>>> +       if (i == ARRAY_SIZE(hci_cc_table)) {
>>> +               /* Unknown opcode, assume byte 0 contains the status, so
>>> +                * that e.g. __hci_cmd_sync() properly returns errors
>>> +                * for vendor specific commands send by HCI drivers.
>>> +                */
>>> +               *status = skb->data[0];
>>> +       }
>>
>> The format of return parameters in command is not defined by the spec:
>>
>> BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E
>> page 2189:
>>
>> Return_Parameters:
>> Size: Depends on command
>>
>> This is the return parameter(s) for the command specified in the
>> Command_Opcode event parameter. See each command’s definition for
>> the list of return parameters associated with that command.
>>
>> So assuming the status is the first by is not quite right, although
>> for the standard ones that seems to be valid, I think the best way to
>> resolve this would have been to check if it a vendor command and then
>> have the driver handle it or perhaps have some means for the driver to
>> register it vendor_cc_table, we can perhaps have this as a workaround
>> for now and only really change how we parse the cc for vendor commands
>> if a vendor decide not to have a status as first parameter but Id
>> probably leave a comment that quoting the spec that reminds us this
>> code may need changing.
> 
> Are you still planning to send updates for this, I consider this quite
> urgent given that it can break support with some vendors.

Right, sorry for being a bit slow. I will prepare + email a version 2
adding a comment that byte 0 being the status is not guaranteed with
vendor commands right away.

Regards,

Hans



> 
>>>         handle_cmd_cnt_and_timer(hdev, ev->ncmd);
>>>
>>> --
>>> 2.37.1
>>>
>>
>>
>> --
>> Luiz Augusto von Dentz
> 
> 
>